Influencing factors analysis of spontaneous knee joint osteoarthritis among middle aged and old aged pople in Xi'an

ObjectiveTo explore the prevalence rate of knee joint osteoarthritis and its pathogenetic features among the middle-aged and old aged people in the urban and rural area of Xi'an.MethodsFrom May to October 2005, 1 538 Han nationality above 40 years in Xi'an were investigated according to stratified and cluster random sampling. The same questionnaire was delivered to subjects who had been given normotopia and lateral position radiographic examination in both knees. Excluded from etiological arthritis, some subjects with clinical symptoms and a radiographic grade (beyond Kellgren & Lawrence grade II) were finally diagnosed as spontaneous knee joint osteoarthritis. All analyses were performed with SPSS 13.0 and t test, U test. Single factor analysis and multiple logistic regression analysis were used to analyze dates.ResultsThe total prevalence of spontaneous knee joint osteoarthritis was 12.1% with 2.5% and 2.1% for right and left knees, respectively. The prevalence of knee joint osteoarthritis in women was 2.5 times of that in men (17.2% vs 6.8%, P = 0.000). the osteophyte prevalence in women was 2.3 times of that in men (26.5% vs 11.4%, P = 0.000). The prevalence of knee joint osteoarthritis and osteophyte increased with the growth of age. So did the symptomatic knee, except for the age group of 56-60 years and 66–70 years. The prevalence of symptomatic knee joint for urban area was significantly higher than that for rural area (56.3% vs 45.3%, P = 0.003). In women, the prevalence of knee joint osteoarthritis increased significantly with the increasing of body mass index, which had not been observed in men. Female and obesity are the risk factors for osteoarthritis, but bean and its products and meat could prevent the osteoarthritis.ConclusionOld age, female and obesity serve as risk factors for knee joint osteoarthritis.